<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		
		<script>
			function b(num){
				if(num<=1){
					return 1;
				}else{
					return num*b(num-1);
				}
			}
			var num=b(5)
			console.log(num)
		</script>
	</body>
</html>
